1. Field of the Invention
The present invention is directed to a method and apparatus for applying a reinforcing liner blank in a desired position on a surface of a box blank prior to attachment thereto and particularly prior to performing a folding and gluing operation on the attached or assembled blanks.
2. Prior Art
In prior art methods and apparatuses for positioning a liner blank on a box blank for subsequent attachment, problems exist in transporting the blanks and positioning the blanks in the desired assembled relationship for attachment.
One device which has been proposed for positioning the engaged blanks in the desired relationship includes a lower endless chain with catches or driving dogs which engage contact dogs which engage a rear or trailing edge of the blanks to move the blanks through the device. It has also been proposed to feed the blanks from a stack onto the moving chains by the use of distributing dogs which engage a trailing edge of a lowermost blank in the stack to shift the blank relative to the stack. To position the liner blank on the box blank, the box blank is conveyed by the chains to a given position and held at that position. The liner blank is conveyed by the other chains to a position above the held box blanks and then released and deposited on the stationary box blank. Then the box blank with the liner blank deposited thereon is transported to the next station.
In the proposed design utilizing contact and distributing dogs, the dogs engage the trailing edge of the blank with an impact which is likely to damage an edge of a blank having a certain board quality. This is especially true of corrugated boards which have a corrugated layer having undulation with parallel extending crests and troughs. If the edge of the blank extends parallel and along a crest or trough of an undulation of the corrugated layer, the resistance of the edge is insufficient. If the edge extends transverse or across a plurality of the undulations, the resistance might be sufficient, but the toughness features are generally inadequate to withstand the impacting blows of the dogs without damage to the edge of the blank.
Another difficulty with transporting the blanks by pushing with dogs engaging a rear or trailing edge is the tendency of the blank to bend or curve upward as it is pushed through the device.
In the above-mentioned proposed device utilizing dogs engaging the trailing edges of the blanks, the reinforcing liner blank is moved to a position and then dropped onto the stationary box blank. This requires a discontinuous motion for the blanks in both time and space.